1. Field of the Invention
The present invention relates to a keypad panel, and in particular to a metallic panel assembly.
2. Description of Prior Art
Keypad panel has become a necessary hardware for an electronic device. The surface of the keypad on the keypad panel is provided with numerals, characters, phonetic symbols, roots for an input method and various functional icons, so that a user can input data or perform various functions of the electronic device. Therefore, for a handheld electronic device, the keypad panel is a very important input means.
For example, a conventional metallic keypad panel on an electronic device is shown in FIGS. 1(a) to 1(f) (Japanese Laid-Open Patent Publication No. 2007-134071). In manufacturing the metallic keypad panel 10a disclosed in FIG. 1, a metallic plate 1a is prepared first, and the metallic plate 1a is attached on a transparent plastic film 2a. Then, the metallic plate 1a is made to have a hollowed portion 3a. The surface of the metallic plate 1a is formed with a transparent resin layer 4a. The bottom of the transparent plastic film 2a is formed with a transparent elastic layer 5a. In manufacturing the transparent elastic layer 5a, via a hot pressing process, the transparent plastic film 2a and the transparent elastic layer 5a are compressed into the hollowed portion 3a together, thereby forming a separating line 21a for separating the metallic keys. Then, a light-emitting layer 6a is attached to the bottom of the transparent elastic layer 5a. 
In manufacturing the above metallic keypad panel 10a, since the transparent plastic film 2a and the transparent elastic layer 5a are compressed into the hollowed portion 3a together, the pressing force and the heating temperature should be properly controlled during the hot pressing process. Otherwise, the transparent plastic film 2a and the transparent elastic layer 5a cannot be compressed into the hollowed portion 3a completely, causing defective products. Even, during the process of compressing the transparent plastic film 2a and the transparent elastic layer 5a into the hollowed portion 3a, the transparent plastic film 2a may rub and pull the wall faces and chamfers of the hollowed portion 3a, causing the breakage of the transparent plastic film 2a easily and the difficulty in manufacture.
Next, gaps are generated easily between the transparent plastic film 2a compressed into the hollowed portion 3a and the wall face of the hollowed portion 3a. The gaps may be filled by dusts or penetrated by liquid, so that the metallic keys cannot be pressed smoothly or an internal short circuit may occur.
Further, the surface of the transparent resin layer 4a formed on the metallic plate 1a is a flat surface, which merely provides a protective effect for the metallic plate 1a without any reflective effect of a particular luster. Therefore, the external appearance and the overall visual effect of the metallic keypad panel 10a are dull.